46. Annually

You have to license your car every year, it should be the same with a gun. The tax does not need to be prohibitive, no more than a license tag for a car. If you don't want to pay the tax, you can turn them in and the tax collector will stop billing you. If you really feel you need one or more for protection, an annual tax of say $50 each is a small price to pay. People pay alot more for alarm systems. As they say, "freedom isn't free".